Generally, a macro base station (macrocell base station) of a communication terminal is placed on a tower having a height of several tens of meters or on the roof of a building or structure. A communication area covered by the macro base station is called as a ‘macrocell’, and the base station configures the mobile telephone network. However, recently, different from the conventional base station, a base station for communication terminal covering a narrow area is proposed. That is a base station for communication terminal (femtocell base station), which can be installed in the user's house. The communication area covered by the femtocell base station is called as ‘femtocell’, this base station is connectable with the mobile telephone network via the internet protocol network. By utilizing this femtocell base station, it is expected that communication between the communication terminals is easily established inside a building, and communication speed can be improved comparing with the outside base station shared by a plurality of users. Moreover, by installing the femtocell base station, it is possible to solve the traffic problems of increasing voice and data communication without enhancement of existing macrocell base station. However, as described below, this femtocell base station requires a new communication method.    Patent Reference 1: Japanese Unexamined Patent Application Publication No. 2003-124872